AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Comparison of Spectroscopic Signatures of Smog Chamber and Atmospheric Aerosols
LYNN RUSSELL, Shang Liu, Kabindra Shakya, Ashley Corrigan, Anita Johnson, Paul Ziemann, John Shilling, Lisa Pfaffenberger, Jay Slowik, Andre Prévôt, Josef Dommen, Urs Baltensperger, Hwajin Kim, Suzanne Paulson, Spyros Pandis, Michael Lewandowski, John Offenberg, Tadeusz Kleindienst, Christine Loza, Jill Craven, Lindsay Yee, Katherine Schilling, John Seinfeld, Scripps Institution of Oceanography, UCSD
Abstract Number: 675 Working Group: Aerosol Chemistry
Abstract The three largest types of sources that emit vapors that form secondary organic aerosol (SOA) are fossil fuel combustion, biomass and biofuel burning, and biogenic vapor fluxes. Each type of vapor emission has a different characteristic mixture of molecular structures – from the long-chain or aromatic-ringed hydrocarbons of fossil fuels to the branched or non-aromatic rings of biogenic vapors, with biomass and biofuel burning vapors having branched, aromatic, and other ringed compounds with some oxidized groups. As these compounds are oxidized by combustion or photochemistry, they add oxygenated groups but retain some of the carbon backbone that characterized the original molecule. Spectroscopic analysis can be used to track the initial hydrocarbon backbones to distinguish different types of oxygenated SOA. In this study, we compare both NEXAFS and FTIR spectra from smog chamber studies with those collected from spectra isolated from atmospheric particles dominated by one of these three SOA source types. Atmospheric SOA associated with combustion sources is consistent with both alkane and aromatic precursors. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and non-acid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in non-acid carbonyl groups in SOA.